Convergence rates of the DPG method with reduced test space degree

This paper presents a duality theorem of the Aubin-Nitsche type for discontinuous Petrov Galerkin (DPG) methods. This explains the numerically observed higher convergence rates in weaker norms. Considering the specific example of the mild-weak (or primal) DPG method for the Laplace equation, two further results are obtained. First, the DPG method continues to be solvable even when the test space degree is reduced, provided it is odd. Second, a non-conforming method of analysis is developed to explain the numerically observed convergence rates for a test space of reduced degree

Wave attenuation at a salt marsh margin: A case study of an exposed coast on the Yangtze estuary

To quantify wave attenuation by (introduced) Spartina alterniflora vegetation at an exposed macrotidal coast in the Yangtze Estuary, China, wave parameters and water depth were measured during 13 consecutive tides at nine locations ranging from 10 m seaward to 50 m landward of the low marsh edge. During this period, the incident wave height ranged from <0.1 to 1.5 m, the maximum of which is much higher than observed in other marsh areas around the world. Our measurements and calculations showed that the wave attenuation rate per unit distance was 1 to 2 magnitudes higher over the marsh than over an adjacent mudflat. Although the elevation gradient of the marsh margin was significantly higher than that of the adjacent mudflat, more than 80% of wave attenuation was ascribed to the presence of vegetation, suggesting that shoaling effects were of minor importance. On average, waves reaching the marsh were eliminated over a distance of similar to 80 m, although a marsh distance of >= 100 m was needed before the maximum height waves were fully attenuated during high tides. These attenuation distances were longer than those previously found in American salt marshes, mainly due to the macrotidal and exposed conditions at the present site. The ratio of water depth to plant height showed an inverse correlation with wave attenuation rate, indicating that plant height is a crucial factor determining the efficiency of wave attenuation. Consequently, the tall shoots of the introduced S. alterniflora makes this species much more efficient at attenuating waves than the shorter, native pioneer species in the Yangtze Estuary, and should therefore be considered as a factor in coastal management during the present era of sea-level rise and global change. We also found that wave attenuation across the salt marsh can be predicted using published models when a suitable coefficient is incorporated to account for drag, which varies in place and time due to differences in plant characteristics and abiotic conditions (i.e., bed gradient, initial water depth, and wave action).

Life after a point-of-care ultrasound course:setting up the right conditions!

Background: Point-of-care Ultrasound (POCUS) is becoming an important diagnostic tool for internal medicine and ultrasound educational programs are being developed. An ultrasound course is often included in such a curriculum. We have performed a prospective observational questionnaire-based cohort study consisting of participants of a POCUS course for internal medicine in the Netherlands in a 2-year period. We investigated the usefulness of an ultrasound course and barriers participants encountered after the course. Results: 55 participants (49%) completed the pre-course questionnaire, 29 (26%) completed the post-course questionnaire, 11 participants (10%) finalized the third questionnaire. The number of participants who performs POCUS was almost doubled after the course (from 34.5 to 65.5%). Almost all participants felt insufficiently skilled before the course which declined to 34.4% after the course. The majority (N = 26 [89.7%]) stated that this 2-day ultrasound course was sufficient enough to perform POCUS in daily practice but also changed daily practice. The most important barriers withholding them from performing ultrasound are lack of experts for supervision, insufficient practice time and absence of an ultrasound machine. Conclusions: This study shows that a 2-day hands-on ultrasound course seems a sufficient first step in an ultrasound curriculum for internal medicine physicians to obtain enough knowledge and skills to perform POCUS in clinical practice but it also changes clinical practice. However, there are barriers in the transfer to clinical practice that should be addressed which may improve curriculum designing

New developments in adult congenital heart disease

Contains fulltext : 225482.pdf (Publisher’s version ) (Open Access)Congenital heart disease (CHD) affects 0.8% of live births and over the past decades technical improvements and large-scale repair has led to increased survival into adulthood of over 95% of the new-born. A new group of patients, those who survived their congenital heart defect, has emerged but late complications including heart failure, pulmonary hypertension (PH), arrhythmias, aneurysms and endocarditis appeared numerous, with a huge impact on mortality and morbidity. However, innovations over the past years have changed the landscape of adult CHD dramatically. In the diagnostic process important improvements have been made in the use of MRI, biomarkers, e‑health concepts and 3D visualisation of anatomy. Care is now concentrated in specialised centres, with a continuous emphasis on education and the introduction of weekly multidisciplinary consultations on diagnosis and intervention. Surgery and percutaneous intervention have been refined and new concepts applied, further reducing the burden of the congenital malformations. Research has matured from case series to global networks. Currently, adults with CHD are still facing high risks of early mortality and morbidity. By global collaboration and continuous education and development and innovation of our diagnostic and therapeutic arsenal, we will improve the perspectives of these young patients

Highly Recommended? How Relation-Specific Attachment Styles Bias Customers Willingness to Recommend

Recently concepts from attachment theory are being applied to business situations. In this paper we focus on how relationship specific (RS) versus general (G) attachment styles affect the willingness-to-recommend (WtR) by customers. Such WtR refers to the likelihood of customers to recommend the services of their service provider to other customers, based on their experiences with the provider. This WtR is often measured by means of the Net Promoter Score (NPS) which is assumed to be a reliable (credible) market signal as it originates from customers themselves and not from the firm. This study provides insights in this issue using data from 798 members of an online panel from the Netherlands, covering four service industries. Customers are surveyed on their RS and G attachment styles, trust in, satisfaction with, and commitment to their service provider, as well as their WtR this provider. Findings emerge from econometric parallel mediation analyses. This study shows that customers' RS but not the G attachment styles bias their appraisal of trust in, satisfaction with and commitment to the service provider, which in turn affects their WtR. More specifically, across the four service industries, customers scoring higher on RS anxiety and/or avoidance show systematically lower levels of trust in and satisfaction with, and commitment to the firm, ultimately leading to lower WtR. Firms should especially target those customers that score higher on RS avoidance (possibly in combination with higher levels of RS anxiety) as their WtR is strongly biased which might create uncertainty for other customers about the firm's reputation